"isotherms in Paris, in 1817. An isogeotherm is a line of equal mean annual temperature. An isocheim is a line of equal mean winter temperature, and an isothere is a line of equal mean summer temperature. An isohel (from or ""helios"", meaning 'Sun') is a line of equal or constant solar radiation. An isohyet or isohyetal line (from or ""huetos"", meaning 'rain') is a line joining points of equal rainfall on a map in a given period . A map with isohyets is called an isohyetal map. An isohume is a line of constant relative humidity, while a isodrosotherm (from"
"Isochrone map An isochrone map (or chart/diagram) in geography and urban planning is a map showing areas related to isochrones between different points. An isochrone is defined as ""a line drawn on a map connecting points at which something occurs or arrives at the same time"". Such a map is sometimes termed simply an isochrone (iso = equal, chrone = time). In hydrology and transportation planning isochrone maps are commonly used to depict areas of equal travel time. The term is also used in cardiology as a tool to visually detect abnormalities using body surface distribution. Isochrone maps have been"
"River linking River Linking is project linking two or more rivers by creating a network of manually created canals, and providing land areas that otherwise does not have river water access and reducing the flow of water to sea using this means. It is based on the assumptions that surplus water in some rivers can be diverted to deficit rivers by creating a network of canals to interconnect the rivers. For an instance, in India the rainfall over the country is primarily orographic, associated with tropical depressions originating in the Arabian Sea and the Bay of Bengal. The summer monsoon"
"is located at the bottom of the picture with a stream flowing through it. Moving up the map, we can say that rainfall which lands on all of the places along the first yellow line will reach the watershed outlet at exactly the same time. This is true for every yellow line, with each line further away from the outlet corresponding to a greater travel time for runoff traveling to the outlet. Furthermore, as this image shows, the spatial representation of travel time can be transformed into a cumulative distribution plot detailing how travel times are distributed throughout the area"
"Potomac River. Numerous cities were founded at the intersection of rivers and the fall line. U.S. Route 1 links many of the fall line cities. Fall line A fall line (or fall zone) is the geomorphologic break that demarcates the border between an upland region of relatively hard crystalline basement rock and a coastal plain of softer sedimentary rock. A fall line is typically prominent when crossed by a river, for there will often be rapids or waterfalls. Many times a fall line will recede upstream as the river cuts out the uphill dense material, often forming ""c""-shaped waterfalls and"
"the entire range for waters which have not undergone excessive evaporation""'. Global meteoric water line The Global Meteoric Water Line is an equation defined by the geochemist Harmon Craig that states the average relationship between hydrogen and oxygen isotope ratios in natural terrestrial waters, expressed as a worldwide average. formula_1 A meteoric water line can also be calculated for a given area, and used as a baseline within that area. Kinetic fractionation will cause the isotope ratios to vary between localities within that area. This relationship is used within the field of isotope hydrology. Craig's original assertion is that ""the"
"Global meteoric water line The Global Meteoric Water Line is an equation defined by the geochemist Harmon Craig that states the average relationship between hydrogen and oxygen isotope ratios in natural terrestrial waters, expressed as a worldwide average. formula_1 A meteoric water line can also be calculated for a given area, and used as a baseline within that area. Kinetic fractionation will cause the isotope ratios to vary between localities within that area. This relationship is used within the field of isotope hydrology. Craig's original assertion is that ""the isotopic enrichments, relative to ocean water, display a linear correlation over"
"or ""drosos"", meaning 'dew', and or ""therme"", meaning 'heat') is a line of equal or constant dew point. An isoneph is a line indicating equal cloud cover. An isochalaz is a line of constant frequency of hail storms, and an isobront is a line drawn through geographical points at which a given phase of thunderstorm activity occurred simultaneously. Snow cover is frequently shown as a contour-line map. An isotach (from or ""tachus"", meaning 'fast') is a line joining points with constant wind speed. In meteorology, the term isogon refers to a line of constant wind direction. An isopectic line denotes"
"or ""projection"" of certain navigational maps. A rhumb line appears as a straight line on a Mercator projection map. The name is derived from Old French or Spanish respectively: """"rumb"""" or ""rumbo"", a line on the chart which intersects all meridians at the same angle. On a plane surface this would be the shortest distance between two points. Over the Earth's surface at low latitudes or over short distances it can be used for plotting the course of a vehicle, aircraft or ship. Over longer distances and/or at higher latitudes the great circle route is significantly shorter than the rhumb"
"areas must need to be rehabilitated to new areas. River linking River Linking is project linking two or more rivers by creating a network of manually created canals, and providing land areas that otherwise does not have river water access and reducing the flow of water to sea using this means. It is based on the assumptions that surplus water in some rivers can be diverted to deficit rivers by creating a network of canals to interconnect the rivers. For an instance, in India the rainfall over the country is primarily orographic, associated with tropical depressions originating in the Arabian"
"be representative for the rainfall on the area of land included in its polygon. These polygons are made by drawing lines between gauges, then making perpendicular bisectors of those lines form the polygons. The isohyetal method involves contours of equal precipitation are drawn over the gauges on a map. Calculating the area between these curves and adding up the volume of water is time consuming. Isochrone maps can be used to show the time taken for runoff water within a drainage basin to reach a lake, reservoir or outlet, assuming constant and uniform effective rainfall. Drainage basins are the principal"
"falls across a series of rapids down to its own tidal estuary. Before navigation improvements such as locks, the fall line was generally the head of navigation on rivers due to their rapids or waterfalls, and the necessary portage around them. The Little Falls of the Potomac River is one example. Because of the commercial traffic, required labor and availability of water power to operate mills, numerous cities were founded at the intersection of rivers and the fall line. U.S. Route 1 links many of the fall line cities. In 1808, Treasury Secretary Albert Gallatin noted the significance of the"
"arid parts of the year. Water gaps of necessity often cut entirely through a barrier range and riverine gaps may create canyons such as the riverine gaps of the Danube River, Lehigh River Gorge, the Colorado River's Grand Canyon and the Genesee River. Such cuttings may expose millennia of strata in the local rock column writing the geologic record. Gap (landform) A gap is a land form that is a low point or opening between hills or mountains or in a ridge or mountain range. It may be called a col, notch, pass, saddle, water gap, or wind gap, and"
"fall line as an obstacle to improved national communication and commerce between the Atlantic seaboard and the western river systems: Some cities that lie along the Piedmont–Coastal Plain fall line include the following (from north to south): Atlantic Seaboard fall line The Atlantic Seaboard Fall Line, or Fall Zone, is a escarpment where the Piedmont and Atlantic coastal plain meet in the eastern United States. Much of the Atlantic Seaboard fall line passes through areas where no evidence of faulting is present. The fall line marks the geologic boundary of hard metamorphosed terrain—the product of the Taconic orogeny—and the sandy,"
"Parting lineation Parting lineation (also known as current lineation or primary current lineation) is a subtle sedimentary structure in which sand grains are aligned in parallel lines or grooves on the surface of a body of sand (or lithified as a sandstone). The orientation of the lineation is used as a paleocurrent indicator, although the precise flow direction (i.e. upstream vs. downstream) is often indeterminable. They are also the primary indicator of the lower part of the upper flow regime bedform. Parting lineation is a sedimentary structure commonly found on the surface of parallel-laminated sandstones. It is aligned with the"
"Fall line A fall line (or fall zone) is the geomorphologic break that demarcates the border between an upland region of relatively hard crystalline basement rock and a coastal plain of softer sedimentary rock. A fall line is typically prominent when crossed by a river, for there will often be rapids or waterfalls. Many times a fall line will recede upstream as the river cuts out the uphill dense material, often forming ""c""-shaped waterfalls and exposing bedrock shoals. Because of these features riverboats typically cannot travel any farther inland without portaging, unless locks are built there. On the other hand,"
"Dry line A dry line (also called a dew point line, or Marfa front, after Marfa, Texas) is an imaginary line across a continent that separates moist air from an eastern body of water and dry desert air from the west. One of the most prominent examples of such a separation occurs in central North America, especially Texas, Oklahoma, and Kansas, where the moist air from the Gulf of Mexico meets dry air from the desert south-western states. The dry line is an important factor in severe weather frequency in the Great Plains of North America. It typically lies north-south"
"a sufficient water supply. Important examples are the Chicago Portage, connecting the Great Lakes and Mississippi by the Chicago Sanitary and Ship Canal, and the Canal des Deux Mers in France, connecting the Atlantic and the Mediterranean. Categories: Drainage divide A drainage divide, water divide, divide, ridgeline, watershed, or water parting is the line that separates neighbouring drainage basins. On rugged land, the divide lies along topographical ridges, and may be in the form of a single range of hills or mountains, known as a dividing range. On flat terrain, especially where the ground is marshy, the divide may be"
"Gap (landform) A gap is a land form that is a low point or opening between hills or mountains or in a ridge or mountain range. It may be called a col, notch, pass, saddle, water gap, or wind gap, and geomorphologically are most often carved by water erosion from a freshet, stream or a river. Gaps created by freshets are often, if not normally, devoid of water through much of the year, their streams being dependent upon the meltwaters of a snow pack. Gaps sourced by small springs will generally have a small stream excepting perhaps during the most"
"border. It is, therefore equivalent to the ""standard parallel"" in the US system. In Ontario, a baseline forms a straight line parallel a geographical feature (mostly a lake, especially Lake Ontario or Lake Erie) that serves as a reference line for surveying a grid of property lots. The result of this surveying is the concession road and sideline system in use today. Baseline (surveying) In surveying, a baseline is a line between two points on the earth's surface and the direction and distance between them. In a triangulation network, at least one baseline needs to be measured to calculate the"
"west side of the Pennines receives more rain than the east because the clouds (generally arriving from the west) are forced up and over the hills and cause the rain to fall preferentially on the western slopes. This is particularly noticeable between Manchester (West) and Leeds (East) where Leeds receives less rain due to a rain shadow of 12 miles from the Pennines. Orography Orography (from the Greek ""όρος"", hill, ""γραφία"", to write) is the study of the topographic relief of mountains, and can more broadly include hills, and any part of a region's elevated terrain. Orography (also known as"
"Drainage divide A drainage divide, water divide, divide, ridgeline, watershed, or water parting is the line that separates neighbouring drainage basins. On rugged land, the divide lies along topographical ridges, and may be in the form of a single range of hills or mountains, known as a dividing range. On flat terrain, especially where the ground is marshy, the divide may be harder to discern. A valley floor divide is a low drainage divide that runs across a valley, sometimes created by deposition or stream capture. Since ridgelines are relatively easy to see and agree about, drainage divides are often"
"north-south line, Eastern Ohio Meridian, was to be the western boundary of Pennsylvania, sometimes called Ellicott‘s Line after Andrew Ellicott, who had been in charge of surveying it, and the first east-west line (called the Geographer’s Line or Base Line) was to begin where the Pennsylvania boundary touched the north bank of the Ohio River, the Beginning Point of the U.S. Public Land Survey. The Geographer’s Line was to extend westward through “the whole territory” which at that time was meant to include lands lying between the Ohio River and Lake Erie. A problem with this plan was that Connecticut"
"formed with a cold front. A weaker form of the dry line seen more commonly is the lee trough, which displays weaker differences in moisture. When moisture pools along the boundary during the warm season, it can be the focus of diurnal thunderstorms. The dry line may occur anywhere on earth in regions intermediate between desert areas and warm seas. The southern plains west of the Mississippi River in the United States are a particularly favored location. The dry line normally moves eastward during the day and westward at night. A dry line is depicted on National Weather Service (NWS)"
"land masses and the bridges connecting them. In modern terms, one replaces each land mass with an abstract ""vertex"" or node, and each bridge with an abstract connection, an ""edge"", which only serves to record which pair of vertices (land masses) is connected by that bridge. The resulting mathematical structure is called a graph. Since only the connection information is relevant, the shape of pictorial representations of a graph may be distorted in any way, without changing the graph itself. Only the existence (or absence) of an edge between each pair of nodes is significant. For example, it does not"
"Rainband A rainband is a cloud and precipitation structure associated with an area of rainfall which is significantly elongated. Rainbands can be stratiform or convective, and are generated by differences in temperature. When noted on weather radar imagery, this precipitation elongation is referred to as banded structure. Rainbands within tropical cyclones are curved in orientation. Tropical cyclone rainbands contain showers and thunderstorms that, together with the eyewall and the eye, constitute a hurricane or tropical storm. The extent of rainbands around a tropical cyclone can help determine the cyclone's intensity. Rainbands spawned near and ahead of cold fronts can be"
"this has been noted in the wake of cold fronts. Rainband A rainband is a cloud and precipitation structure associated with an area of rainfall which is significantly elongated. Rainbands can be stratiform or convective, and are generated by differences in temperature. When noted on weather radar imagery, this precipitation elongation is referred to as banded structure. Rainbands within tropical cyclones are curved in orientation. Tropical cyclone rainbands contain showers and thunderstorms that, together with the eyewall and the eye, constitute a hurricane or tropical storm. The extent of rainbands around a tropical cyclone can help determine the cyclone's intensity."
"Flanking line (meteorology) A flanking line is an area of cumulus congestus or small cumulonimbus that mark an area of widespread updrafts in front of strong thunderstorms. These flanking lines generally occur in the vicinity of supercell thunderstorms or large multicell thunderstorms. A flanking line often has a stairstep appearance where the tallest cells are connected to the main cumulonimbus. Figure 1 shows this layering: The bases of the clouds making the flanking line are merged. The forefront area usually has no precipitation. In the picture, it is possible to detect precipitation in the background just above the horizon below"
"Reach (geography) A reach is a length of a stream or river, usually suggesting a level, uninterrupted stretch. The beginning and ending points may be selected for geographic, historical or other reasons – and may be based on landmarks such as gauging stations, river miles, natural features, and topography. A reach may also be an expanse, or widening, of a stream or river channel. This commonly occurs after the river or stream is dammed. A reach is similar to an arm. The term ""reach"" can also refer to: As of 2015, the US Board on Geographic Names records 334 place"
"first north-south line, Eastern Ohio Meridian, was to be the western boundary of Pennsylvania, sometimes called Ellicott‘s Line after Andrew Ellicott, who had been in charge of surveying it, and the first east-west line (called the Geographer's Line or Base Line) was to begin where the Pennsylvania boundary touched the north bank of the Ohio River, the Beginning Point of the U.S. Public Land Survey. The Geographer's Line was to extend westward through “the whole territory” which at that time was meant to include lands lying between the Ohio River and Lake Erie. A problem with this plan was that"
"relative warm bodies of water such as the Great Lakes. If the atmosphere is cold enough, these rainbands can yield heavy snow. Rainbands in advance of warm occluded fronts and warm fronts are associated with weak upward motion, and tend to be wide and stratiform in nature. In an atmosphere with rich low level moisture and vertical wind shear, narrow, convective rainbands known as squall lines generally in the cyclone's warm sector, ahead of strong cold fronts associated with extratropical cyclones. Wider rain bands can occur behind cold fronts, which tend to have more stratiform, and less convective, precipitation. Within"
"is the following: In geodesy, the science of measuring Earth's size and shape, a geodesic (from Greek ""geo"", Earth, and ""daiein"", to divide) is the shortest route between two points on the Earth's surface. Approximately, such a route is a segment of a great circle, such as a line of longitude or the equator. These paths are certainly not straight, simply because they must follow the curvature of the Earth's surface. But they are as straight as is possible subject to this constraint. The properties of geodesics differ from those of straight lines. For example, on a plane, parallel lines"
"Plain In geography, a plain is a flat, sweeping landmass that generally does not change much in elevation. Plains occur as lowlands along the bottoms of valleys or on the doorsteps of mountains, as coastal plains, and as plateaus or uplands. In a valley, a plain is enclosed on two sides, but in other cases a plain may be delineated by a complete or partial ring of hills, by mountains, or by cliffs. Where a geological region contains more than one plain, they may be connected by a pass (sometimes termed a gap). Coastal plains would mostly rise from sea"